Can you mix gigabit and 10/100 ethernet on the same network?

Question

I have an Apple Airport Extreme Gigabit router and some new machines I need to put on my network (PS3, Mrs' laptop etc.) but the router has only got four ports so I was thinking of getting a simple, unmanaged gigabit switch to increase this.

I also have a 10/100 switch which I decommissioned when I got the Apple router as I was under the impression using it would make all the network traffic run at 10/100 speed. I'm not sure this assumption was correct ...

Ideally I'd like to have a gigabit and 10/100 running on the same network so that the older boxes could use the latter while the machines that have gigabit ethernet onboard could run at modern speeds. Is this possible on a single network or should I get two gigabit switches?

Schematic diagram to illustrate what I mean. Sorry, looks like ploader.net has gone the way of the Dodo.

Thanks.

Solution

Gigabit or 100Mbit (or 10Mbit) will be decided on a link by link basis, and it is possible to mix the two within a network. Each router/switch should automatically negotiate the fastest link speed (although sometimes it's better to specify this manually, if possible).

So, it makes sense to group all 100Mbit hardware with your existing 100Mbit switch; likewise for the Gigabit hardware and router. It will not slow down the Gigabit section of the network.

Comments

[cybernard]

In the ancient history when hubs were current, then you couldn't mix and match, without a lowest common denominator downgrade. However, almost any modern switch can handle it.

[Alex Cannon]

There is also the issue of Gigabit's jumbo frames not being usable on the network, and data sent through Gigabit links overrunning the buffers in switches that are reducing the speed to 100mb, and the role that flow control (IEEE 802.3x and 802.1Qbb) plays in this. Some more answers might be helpful!

[5arx]

Great. Thanks for your response. I've ordered the switch ... :-)

[Max Hodges]

so this answers states that yes you can mix them, and the switch should negotiate the fastest speed, but that speed might be 100 not 1000 mbps for your gigabit devices right?

[Max Hodges]

how do you group your 100mbit hardware? by daisy chaining a 100mbit switch to your 1 gbit switch? Is that a good idea?

[sblair]

@MaxHodges As noted in the link, sometimes auto-negotiation doesn't work properly, so it's better to manually configure the gigabit ports on your switches. I'm not sure what you mean by daisy chaining? If you just mean connecting, then the 100 Mbit links will not affect the speed of any gigabit links. But the overall transfer speed of any data travelling through the 100 Mbit portion of a network will obviously be "bottlenecked" by the 100 Mbit links.

[Max Hodges]

Well when you wrote it makes sense to "group all 100mbit hardware on your existing 100mbit switch" then do you connect (daisy chain) that 100mbit switch to your 1 gigabit switch?